Laser endodontic procedures utilizing alcohol based indocyanine green solutions

ABSTRACT

A method of endodontic therapy with improved disinfection and ablation characteristics may feature the use of an alcohol or polyol-based indocyanine green (ICG) solution with a laser system that emits a wavelength within the maximal absorption range of ICG. By matching the dye and laser output, radiant energy use is maximized for efficient ablation and disinfection of treated tissues. Also, the use of an alcohol or polyol as a solvent for the ICG solution increases the inherent disinfection qualities of the solution itself. In one embodiment, the prepared canal is flooded with the ICG solution and the laser activates with the laser fiber inserted into the solution. In an alternate embodiment, the solution is mostly removed prior to activation of the laser, but only after necrotic tissue has been stained.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present invention claims priority as a divisional of prior filedU.S. application Ser. No. 17/804,765, filed on May 31, 2022, andincorporates the same by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to the field of dentistry and moreparticularly relates to a therapeutic procedure coupling laser treatmentwith indocyanine green (“ICG”) to enhance disinfection and ablation oftissues to be treated.

BACKGROUND OF THE INVENTION

During contemporary root canal therapy treatments there is a need forremoving necrotic tissue and disinfecting the canal. The prospect ofutilizing a laser to carbonize necrotic tissue and disinfect the canalwith radiant energy is of great interest to clinicians because of theapparent “ease of use” it adds to current standard procedures. Thepossibility of placing a dye into the root canal that is matched toabsorb the wavelength of the treatment laser is also of great interest,because it requires the use of a single laser with one wavelength outputand there is no need to purchase multiple lasers for different materialsubstrates; since the dye is matched to absorb the treatment lasersradiant energy output it will efficiently lase whatever surface to whichthe dye is applied.

The present invention has found a synergistic means of easily deliveringindocyanine green (ICG) into the root canal while concordantlyincreasing the penetration into soft tissue, increasing the waterchasing efficiency, increasing the staining of necrotic tissue, andincreasing the overall anti-microbial effect by the introduction ofalcohols into indocyanine green (ICG) solutions. The present inventionrepresents a departure from the prior art in that the methodologyefficiently utilizes ICG in conjunction with laser therapy for enhancedtreatment.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the known types ofendodontic therapy, an improved method of endodontic therapy may providea solution of ICG which is applied to a treatment area beforeirradiation of said area by an 810 nm diode laser. The method shouldmeet the following objectives: that it be easy to administer andimplement, that it has a degree of familiarity with currentmethodologies, that the materials be inexpensive to manufacture, thatthe methodology be effective in both disinfection and as an aid totissue ablation in an endodontic procedure. As such, a new and improvedmethodology may comprise the introduction of an organic based ICGsolution to a treatment area before irradiation to accomplish theseobjectives.

The more important features of the invention have thus been outlined inorder that the more detailed description that follows may be betterunderstood and in order that the present contribution to the art maybetter be appreciated. Additional features of the invention will bedescribed hereinafter and will form the subject matter of the claimsthat follow.

Many objects of this invention will appear from the followingdescription and appended claims, reference being made to theaccompanying drawings forming a part of this specification wherein likereference characters designate corresponding parts in the several views.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangements of the componentsset forth in the following description or illustrated in the drawings.The invention is capable of other embodiments and of being practiced andcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein are for description andshould not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, methods, and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above-recited and other

advantages and features of the invention can be obtained, a moreparticular description of the invention briefly described above will berendered by reference to specific example embodiments thereof which areillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are therefore notto be considered as limiting of its scope, the invention will bedescribed and explained with additional specificity and detail using theaccompanying drawings.

FIG. 1 is a schematic view depicting one embodiment of an endodontictreatment.

FIG. 2 is an alternate schematic view depicting another embodiment of anendodontic treatment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the endodontic therapy method are hereindescribed. It should be noted that the articles “a”, “an”, and “the”, asused in this specification, include plural referents unless the contentclearly dictates otherwise.

The preferred dye of the present invention is Indocyanine Green (ICG),and the preferred laser is an 810 nm laser, both of which arecommercially available. Indocyanine Green has a maximum absorption rangebetween 780-820 nm; therefore, any laser emitting radiant energy withinthese wavelength parameters would be sufficient to activate IndocyanineGreen at relative high efficacy. The readily available 810 nm diodelaser is therefore ideally suited to use in this methodology.

Indocyanine Green is soluble in water, alcohols and liquid polyols;however, it is known to be unstable in water. An embodiment of thepresent invention utilizes mono-alcohols such as: ethyl, methyl,isopropyl, n-propyl, butyl alcohol and any other alcohols that areliquids as the solvent for ICG. Another embodiment of the presentinvention utilizes poly-ols (which may be generally categorized with“alcohols” for purposes of this application) such as glycerin, propyleneglycol, polyethylene glycols and any other polyols that are liquids.Additional embodiments of the present invention utilize mixtures oforganic solvents with and without water to customize individualcharacteristics for the delivery of soluble ICG such as: capillaryaction, water chasing efficiency, anti-microbial properties, substratestaining efficacy and other characteristics. A preferred embodiment ofthe present invention utilizes ethanol as the best choice of alcohol ofout of many possible alcohols because of its combined superiorattributes namely: low toxicity, excellent water chasing capability,excellent anti-microbial activity, and increased tissue stainingproperties—especially when staining necrotic tissue.

While many embodiments of the present invention incorporate 100% organicsolvents when manufacturing ICG solutions, other embodiments incorporateat least some quantity of water in the formulation. The possible rangesof alcohol to water ratios are:

-   -   Most Preferred Formulation Range: 90%-100% alcohols+% 10-0.0%        water.    -   Preferred Formulation Range: 70%-99.9% alcohols+30%-0.1% water.    -   Less Preferred formulation Range: 5%-99% alcohols+95%-1% water.

ICG solutions that contain higher ratios of organic solvents to waterconcentrations become increasingly more combustible when activated by amatching laser, which in turn helps facilitate the disinfection andremoval of necrotic tissue in the canal. It is important to note thatthis is not possible with 100% ICG\water solutions. The organic alcoholsthat make up the solvent in these ICG solutions burn or conflagratelocally when energized by sufficient radiant energy. The use of analcohol based ICG solution together with the matched laser createsextreme local ablation within a very short time frame, usually a fewseconds. The synergy of the combined effect of the laser, ICG dye, andthe organic solvents creates the localized “synergistic firestorm”designed to adequately ablate necrotic tissue and disinfect the canal.

While many embodiments of ICG solutions can be identified, twomethodologies of root canal therapy utilizing lasers matched to ICGsolutions are found to have additional promise. The first method isdesigned to flood an extirpated root canal with ICG solution and insertthe fiber optic cable tip into the canal while the canal is full ofsolution. The laser is then activated while the cable tip is submergedwithin the pooled ICG solution. Radiant energy produced by the laser istransferred to the ICG solution, resulting in localized heat,combustion, cavitation, and the production of secondary light emission.

The preferred treatment method for this embodiment, shown in FIG. 1 , isto first gain access to the pulp chamber of the tooth (10) byconventional means such as with a high-speed handpiece, and thenextirpate the necrotic root with endodontic files (as per the priorart). After these initial steps, ICG dye solution is introduced into thecanal and pooled (26) in the exposed canal (14). Time for the solutionto infiltrate residual soft tissues may be provided. After sufficienttime has elapsed, which may be no time, an unclad end (22) of a fiberoptic (20) connected to the radiant energy source, in this preferredcase an 810 nm diode laser, is then inserted into the canal (14) and the810 nm diode laser initiated. Upon absorption of emitted radiant energy(24), the ICG dye efficiently heats to such an extent that it begins toboil and evaporate. Then, after the solution is evaporated, the laserwill burn residual necrotic tissue (16) which has been stained in thepresence of the dye. The entire length of the canal (14) is treated fromthe root apex (12) to the coronal portion of the tooth (18) by slowlymoving the tip in and out of the root canal (14) multiple times duringthe treatment. After laser treatment, the canal (14) may be furthertreated with an antiseptic rinse, as would also be customary in theprior art, to kill residual pathogens and to rinse combusted tissuesfrom the canal (14).

The second embodiment of the method (FIG. 2 ) also first floods the rootcanal (14) with ICG solution, allowing the solution to penetrate thenecrotic tissue (16). After sufficient dwell time, the bulk of the ICGsolution is removed with a paper point leaving only a residual amount ofICG solution in the canal (14) and stained necrotic tissue (16). Thefiber optic cable tip (22) is then inserted into the dried canal (14)and the laser is activated wherein the radiant energy produced (24) istransferred to the residual ICG solution resulting in localized heat,combustion, carbonization, and the production of secondary lightemission. This method of activation produces significantly more localheat than the above first method.

Although the present invention has been described with reference topreferred embodiments, numerous modifications and variations can be madeand still the result will come within the scope of the invention. Thedescribed embodiments are to be considered in all respects only asillustrative and not restrictive. No limitation with respect to thespecific embodiments disclosed herein is intended or should be inferred.Therefore, the scope of the invention is indicated by the appendedclaims rather than by the foregoing description. All changes which comewithin the meaning and range of equivalency of the claims are to beembraced within their scope.

What is claimed is:
 1. A root canal therapy treatment for removingnecrotic tissue and disinfecting the root canal comprising: a first stepof preparing a root canal, including removing most of the necrotictissue therefrom and leaving some residual necrotic tissue behind; asubsequent step of flooding the canal with a solution of indocyaninegreen and allowing the solution dwell in the canal; a further step ofremoving at least a portion of the solution of indocyanine green afternecrotic tissue has been stained; a still further step of inserting afiber optic laser tip into the canal; activating a laser in operativeconnection with the fiber optic laser tip emit a laser beam withsufficient radiant energy to carbonize the residual necrotic tissuewithin the canal.
 2. The root canal therapy treatment of claim 1, thelaser being an 810 nm diode laser.
 3. The root canal therapy treatmentof claim 1, the solution of indocyanine green utilizing ethanol as asolvent.
 4. The root canal therapy treatment of claim 1, the solution ofindocyanine green utilizing a solvent with a concentration of at least90% alcohol.
 5. The root canal therapy treatment of claim 1, furthercomprising a step of moving the fiber optic laser tip within the canalwhile the laser is activated, wherein the canal may be better exposed tothe radiant energy of the laser.
 6. A root canal therapy treatment forremoving necrotic tissue and disinfecting the root canal comprising: afirst step of preparing a root canal, including removing most of thenecrotic tissue therefrom and leaving some residual necrotic tissuebehind; a subsequent step of flooding the canal with a solution ofindocyanine green and allowing the solution dwell in the canal; afurther step of removing at least a portion of the solution ofindocyanine green after necrotic tissue has been stained; a stillfurther step of inserting a fiber optic laser tip into the canal;activating a laser in operative connection with the fiber optic lasertip emit a laser beam with sufficient radiant energy to ablate theresidual necrotic tissue within the canal.
 7. The root canal therapytreatment of claim 6, the laser being an 810 nm diode laser.
 8. The rootcanal therapy treatment of claim 6, the solution of indocyanine greenutilizing ethanol as a solvent.
 9. The root canal therapy treatment ofclaim 6, the solution of indocyanine green utilizing a solvent with aconcentration of at least 90% alcohol.
 10. The root canal therapytreatment of claim 1, further comprising a step of moving the fiberoptic laser tip within the canal while the laser is activated, whereinthe canal may be better exposed to the radiant energy of the laser.